Attention is drawn to Note (3) after the title of section C, which Note indicates to which version of the periodic table of chemical elements the IPC refers.

In this subclass , organic acid salts, alcoholates, phenates, chelates or mercaptides are classified as the parent compounds.

Compounds containing Se or Te are classified with their sulfur homologues

A hydrocarbon chain is considered to be terminated by a heteroatom or by a carbon atom having three bonds to heteroatoms with at the most one to halogen

When groups, e.g. aromatic or aliphatic groups, are mentioned without further indications, it means that the group concerned can be further substituted. Otherwise it will be indicated, e.g. C07F 9/11 with hydroxyalkyl compounds without further substituents on alkyl.

WARNINGS

The following IPC groups are not in the CPC scheme. The subject matter for these IPC groups is classified in the following CPC groups:

{at least one of the hetero rings does not contain nitrogen as ring hetero atom} [2013-01]

C07F 9/6561

. . .

containing systems of two or more relevant hetero rings condensed among themselves or condensed with a common carbocyclic ring or ring system, with or without other non-condensed hetero rings [2013-01]